1. Technical Field
This application relates, in general, to surgical stapling apparatus, and more particularly, to atraumatic surgical fasteners for use therewith.
2. Background of Related Art
Many varieties of surgical fastening apparatus are known in the art, some of which are specifically adapted for use in various surgical procedures including, but not limited to, end-to-end anastomosis, circular end-to-end anastomosis, open gastrointestinal anastomosis, endoscopic gastrointestinal anastomosis, and transverse anastomosis. Suitable examples of apparatus which may be used during the course these procedures can be seen in U.S. Pat. Nos. 5,915,616; 6,202,914; 5,865,361; and 5,964,394.
In general, a surgical fastening apparatus will include an anvil that is approximated to a fastener cartridge (or fastener cartridge approximated to an anvil) during use. The anvil includes depressions that are aligned with, and/or are in registration with, slots defined in the cartridge through which the fasteners will emerge, to effectuate formation. The fastener cartridge typically has one or more rows of fasteners disposed laterally or radially of a channel. The channel can be configured to accommodate a knife, or other such cutting element, such that tissue can be simultaneously cut and joined together. Depending upon the particular surgical fastening apparatus, the rows of fasteners may be arranged in a linear or non-linear, e.g. circular, semi-circular, or otherwise arcuate configuration.
Various types of surgical fasteners are well known in the art, including but not limited to unitary fasteners and two-part fasteners. Unitary fasteners generally include a pair of legs adapted to penetrate tissue and which extend from a backspan. In use, subsequent to formation, some of the unitary fasteners have a “B” configuration. Typically, the two-part fastener includes legs that are barbed and extend from a backspan which are engaged and locked into a separate retainer piece that is usually located in the anvil. In use, the two-part fastener is pressed into the tissue so that the barbs penetrate the tissue and emerge from the other side where they are then locked into the retainer piece. The retainers prevent the two-part fastener from dislodging from the tissue. The two-part fasteners are not intended to be unlocked or removable. These fasteners are generally made of a bioabsorbable material.
During each of the aforementioned surgical procedures, the tissue is initially gripped or clamped such that individual fasteners can be ejected from the cartridge, through the slots, and forced through the clamped tissue. Thereafter, the fasteners are formed by driving them into the depressions formed on the anvil (or into locking retainers).
In staplers of the general type described above, it is conventional to provide separate anvil slots at each staple forming location. This makes it necessary to maintain relatively stringent alignment between the staple holding assembly and the anvil to assure that the staples enter the anvil slots correctly for proper clinching. The importance of maintaining good alignment between the relatively movable staple holding assembly and anvil assembly may contribute to the complexity of the instrument and to the cost of manufacturing and maintaining it. It is important that every staple be formed properly since an incompletely or improperly formed staple may leave a gap in a wound closure.